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AMSOIL 100% Synthetic normal, and RACING Motor oils, Lubricants.
What Does oil do?


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Head to Head on the Dyno
Why Change Oil?
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Bosch VS NGK spark plugs
Oil Additives friend or foe

What Does Motor Oil Do?


The type of driving you do, the climate in which you live, and the age of the vehicle, the manufacturer's recommendations all have a bearing on the type of oil you should be using. An added factor in your car/truck's life and performance is related to how you handle the most routine aspect of any vehicle's maintenance - the frequency of oil changes or, more importantly, THE TYPE OF OIL YOU USE!

Yes, it DOES make a difference! Only with AMSOIL can you extend drain intervals to 35,000 miles and also expect IMPROVED fuel economy and engine protection.

   What Is An Oil's Job?

The biggest responsibility of any oil is to form a layer between metal surfaces of various engine parts, in a transmission or in the differentials. This layer is what provides the lubrication characteristics of any oil.

Oil serves as a sealant, filling the microscopic ridges and valleys found in any metal surface, increasing the engine's efficiency.

Oil must serve as a cleaning function, carrying away dirt or other debris which damages bearings or other parts which operate in tight tolerances. Debris is removed through the engine oil filter or the transmission filter. One of the benefits of AMSOIL is that it is the "best cleaner there is" and as a result the longer you use the oil the CLEANER the engine becomes!

Oil uses detergent additives to combat combustion by-products. Burning gasoline (or diesel fuel) produces acids, moisture, soda, ash and other contaminants. The detergent fights these by-products, inhibiting their buildup as sludge, varnishes, etc.

Oil is a tremendous coolant. In the engine, the oil cools the underside of the pistons, valve springs, camshaft, rods, crankshaft and bearings. The oil picks up the heat from the combustion of fuel, as well as friction, and takes it away (no matter how good the oil may be, there is always friction). The volume of the oil in the crankcase helps transfer the heat, but where a car/truck is used in high temperature climates, for hauling trailers or heavy loads, an engine oil cooler is sometimes recommended.

By using AMSOIL 100% Synthetic Oil the engine will remain COOL even in the harshest conditions. AMSOIL will cause the average engine to operate 30 degrees to 50 degrees cooler than normal! That could very likely eliminate the need for an oil cooler altogether.

Oil is the only coolant in your automatic transmission. There's a small radiator within the engine's radiator to take the heat away. When your vehicle is used in high temperature climates, hauling trailers or heavy loads, synthetic ATF is highly recommended. Again, AMSOIL ATF will run MUCH COOLER than any conventional fluid and the oil itself will handle FAR MORE heat than any other oil!

The type and condition of the oil chosen is important. Oil comes in a wide variety of ratings and viscosities, designed for particular applications or vehicle age. With so many choices, a car/truck owner has to know the proper viscosity and API rating recommended for his particular vehicle.

Matching Oil to the Way You Drive:

While you drive, you subject your engine to varying conditions, including:

  • Stop and go driving in town at low speeds
  • Constant high speed freeway driving
  • Very High temperatures
  • Very low temperatures
  • Varying loads

Each puts stress on your car/truck's engine oil. In fact, just starting the engine places extreme stress on the engine's oil, especially in winter weather.

The next time you change your oil, take a minute and think about the following: how you drive, the conditions you encounter - on the street or highway - and the environments your car or truck operates in. Do you do mostly stop and go driving, or is it mostly open freeway driving? Is the outside temperature very hot, or very cold? Do you frequently tow trailers or haul heavy loads? Is your vehicle an older model, with lots of miles, or a newer model?

The way you define your driving habits, environment and the loads you haul or tow, plus the age of your car or truck, will help determine which type and grade of oil you select. No matter what conditions you encounter, AMSOIL 100% Synthetic Oil offers you the right combination of premium engine oils to give your car/truck's engine the proper protection it needs. ONLY AMSOIL can protect you from what is called: "Dry Engine Start-Up"! AMSOIL always leaves a film of oil on surfaces preventing "metal to metal wear" during cold starts!


One of the main areas of concern of any car/truck owner is the viscosity of the oil. The term "weight" has been applied to viscosity for a number of years, but it has nothing to do with how much the oil weighs. On any oil container, the viscosity is clearly marked, with numbers like SAE 0W-30 5W-30, 10W-40, 20W-50, etc.

What do the numbers mean?

Viscosity is defined as the physical property of any fluid to resist flow when pressure is applied. The Society of Automotive Engineers (SAE) uses a numbering system to represent an oil's viscosity at a specific temperature. The higher the number, the more resistant it is to flow. The lower the number, the easier it flows. This allows you to make an "apples to apples" comparison of various oils.

Engine oils must operate in very difficult environments, plus perform a number of important tasks:

  • It must flow easily at temperature well below zero.
  • It must supply lubrication at very high temperatures (in excess of 250F).

Lower viscosity oils flow well at very low temperatures, they are the choice for severe winter operation. Obviously, the ability to flow readily is critical to start your vehicle's engine in brutal cold, and calls for a lower viscosity, such as 0W or 5W viscosity grade.

For protection against high engine operating temperatures, oil must be able to function and provide the needed lubrication. When the vehicle is operating in summer heat, with temperatures above 80 to 90 degrees day after day, the need is for a high viscosity oil.

But do you want to change grades of oil every time the weather gets warmer or colder? Probably not. This is why there are engine oils with two viscosities on the market, known as "multi-viscosity" oils. These oils carry the low temperature flow, and high temperature lubrication properties of the two oils, such as a 0W-30. The "W" refers to winter, with a special additive package to give better cold weather starting performance. As an example, under high heat, OW-30 will have the same flow characteristics as a 10W-30 because their "high numbers" are the same.

AMSOIL Synthetic Oils will handle both the high heat of the Desert Southwest or the cold cranking demanded in Alaska! Many of AMSOIL's pour points are as low as 76 degrees BELOW Zero!

The issue of engine oil volatility is an important one to every car or truck owner, yet few know about it. Volatility is related to viscosity. Volatility is defined as the characteristic of liquids to become a vapor when heat is applied. A liquid is said to have "high" volatility if it tends to evaporate when heat is applied, and "low" volatility if it tends to remain a liquid when the same amount of heat is applied.

To meet the federal government's fuel mileage standards, auto makers tell owners to use lower viscosity oils. Unfortunately, low viscosity oils tend to evaporate more easily than high viscosity oils. The problem: Using a low viscosity oil generally leads to what appears to be an oil consumption problem, when actually the problem is evaporation - the most fuel efficient oils evaporate most readily.

AMSOIL's Lubricants evaporate at a FAR LOWER rate than do other conventional or SYNTHETIC oils! Many of AMSOIL's Oils will only evaporate at a rate of about 5-6% where conventional and other synthetic oils will evaporate at a rate as high as 20% or more! THAT IS A LOT OF OIL GOING INTO OUR ENVIRONMENT! The more AMSOIL is used the more it does for our environment!

Potential Problem Areas

Oil Consumption: More volatile oils mean higher oil consumption; less volatile oils mean less oil consumption.

Starting Friction: If the lighter parts of the oil evaporate, the remaining oil will not provide the proper low temperature starting characteristics.

Engine Deposits: An oil in a vapor state is more likely to decompose, forming harmful deposits (varnish, sludge), than oil in a liquid state.

Heat Stress: Less oil in the pan results in higher engine temperatures. Higher oil temperatures lead to greater evaporation, more oxidation, more deposits and shorter engine life.

Engine Wear: If the oil thickens, greater wear will occur on starting. The oil's anti-wear additives will be used to fight oxidation, rather than prevent wear.

AMSOIL's Oils are designed to overcome ALL of the above problems!


AMSOIL includes a number of additives in its oils to improve their protective qualities. AMSOIL chemists and engineers are able to add many beneficial features to reduce wear, oxidation, evaporation, deposits and many other problems, resulting in a top quality product. When AMSOIL purchases "additives" they only purchase the very highest quality additives made. NO OTHER OIL COMPANY USES AN ADDITIVE "PACKAGE" THAT COMES CLOSE TO AMSOIL.

An additive package aids in improving the oil's life. Remember, nothing lasts forever. Additives are like the oil they help - they have a limited life. Because of the quality of AMSOIL's additives, AMSOIL Lubricants can far exceed the extended drain intervals recommended by AMSOIL!

Some of the additives are:

Detergents: Keep high temperature engine parts, such as pistons and rings, clean and free from deposits.

Dispersants: Suspend and disperse materials that could form varnishes, sludge, etc., clogging the engine.

Anti-wear: Gives added film strength to prevent wear of heavily loaded surfaces (like the crankshaft's rod and main bearings).

Friction Modifiers: Reduce friction losses throughout the engine for more power and better fuel mileage.

Corrosion Inhibitors: Fight the rust and wear caused by acids and moisture. They protect vital steel or iron parts from rust, and corrosion of other metals.

Oxidation Inhibitors: Oxygen can combine with oil (even the best ones) at high engine temperatures to form damaging materials. These additives reduce thickening of the oil, and sludge formation.

Foam Inhibitors: The spinning of the crankshaft and the rods introduces great air turbulence in the crankcase, causing oil to form bubbles (foam). These additives limit bubble growth and break them up quickly. This keeps foam levels low, allowing the oil pump to circulate oil, not oil and air, through the engine.

Viscosity Index (VI) Improver: A VI Improver adds to oil's natural tendency to fight viscosity change with temperature variations. Because of the way AMSOIL is constructed (that's right, CONSTRUCTED) many of our oils DO NOT NEED VI IMPROVERS! It is already built into the Synthetic Base Stock!

Pour Point Depressant: This additive improves a winter oil's ability to flow at very low temperatures. This is not really needed in AMSOIL because the inherent ability of synthetic base stocks to flow in cold conditions (remember, in many instances as low as 76 degrees below zero!).

Service Class:

The Owner's Manual for your car/truck will specify which API Service rating you must use to meet the warranty requirements, depending on whether your engine is a gasoline engine or a diesel. Gasoline engine oils are designated with SG or SH (and now, SJ). Diesel engine oil is designated with CD, CD-II, CE, CF, CF-2, CF-4, or CG-4. Some oils are rated for both gasoline and diesel applications, others are not. For example, an oil with a designation of SJ/CG-4 may be used in both gasoline and diesel engines in light trucks.

The SJ rating is the most current, with the most sophisticated additive packages to combat the effects discussed above. This service designation can replace all oils designated SC to SH. For diesels, ratings are based upon service applications. The latest is CG-4, which can be used to replace all other (except CF-2 and CD-II, a two-cycle diesel engine oil). If you have a question, I can assist you with getting the right service and viscosity ratings. When in doubt, a good rule of thumb is: Go with the best-the SJ rating (gasoline engines).

When to Change Oil:

When using a petroleum oil, generally oil change intervals should not be extended beyond 5,000 miles. With the high stress applied to the lubricants in today's high temperature, high performance engines, petroleum oils begin to break down almost immediately. If I was using a conventional petroleum oil in my vehicle, I would probably change it every 3,000 miles. For more information regarding why petroleum oils break down so much more quickly than high quality synthetics, see our "Why Senthetics".

When using AMSOIL 0W-30, AMSOIL recommends that the oil be changed every 35,000 miles! If you are using the AMSOIL Oil Filter, it should be changed every 12,500 miles and a quart of oil added to replace what was lost in the filter and from what little burn-off may have occurred. Change intervals for our other standard synthetics (such as our 5W-30 and 10W-30) are clearly marked on the container, usually 25,000 miles for gasoline engines. AMSOIL Oil Changes can be extended to 100,000 miles and beyond by using the AMSOIL Bypass Filter (please see this link for more information:

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